From: Lukas Krickl <lukas@krickl.dev>
Date: Mon, 22 Sep 2025 03:43:32 +0000 (+0200)
Subject: rectangle: Added routines to get each point in a rectangle
X-Git-Url: https://git.krickl.dev/?a=commitdiff_plain;h=a197a20d6b5b6d9e7b91bf0e9d0cc6c3a55a678d;p=gbrg%2F.git

rectangle: Added routines to get each point in a rectangle
---

diff --git a/src/rectangle.s b/src/rectangle.s
index 3e18848..63c4580 100644
--- a/src/rectangle.s
+++ b/src/rectangle.s
@@ -80,38 +80,93 @@ rect_find_slot:
 	ld hl, 0
 	ret
 	
-	; tests if any point
-	; of r1 is inside r2
+
+	; gets top left of a rectangle
 	; inputs:
-	;		de: r1
-	;		hl: r2
+	;		hl: rectangle
 	;	returns:
-	;		a == 1: inside
-	;		a == 0: not inside
-rect_test:
-	ld a, [de]
-	ld b, a
+	;		de: y/x
+rect_tl:
+	inc hl ; skip mask
+	ld a, [hl+]
+	ld d, a ; d = y
+	ld a, [hl+]
+	ld e, a ; e = x
+
 	ld a, [hl]
-	; check if masks have a match
-	; otherwise skip
-	and a, b
-	cp a, 0
-	jp z, @no_collision_mask_match
+	ld l, a
+	ld a, d
+	sub a, l ; y-height
+	ld d, a ; d = top left y
+	ret
 	
+	; same as rect_tl
+	; bototm left
+rect_bl:
+	inc hl ; skip mask
+	ld a, [hl+]
+	ld d, a ; d = y
+	ld a, [hl] 
+	ld e, a ; e = x
 	ret
-@no_collision_mask_match:
-	ld a, 0
+	
+	; same as rect_tl
+	; top right
+rect_tr:
+	inc hl ; skip mask
+	ld a, [hl+]
+	ld d, a ; d = y
+	ld a, [hl+]
+	ld e, a ; e = x
+	inc hl ; skip height
+
+	ld a, [hl]
+	add a, e ; e = x + width
+	ld e, a 
+
+	dec hl ; go back to height
+	ld a, [hl]
+	ld l, a
+	ld a, d
+	sub a, l ; y-height
+	ld d, a ; d = top right y
 	ret
 	
+	; same as rect_tl
+	; bottom right
+rect_br:
+	inc hl ; skip mask
+	ld a, [hl+]
+	ld d, a ; d = y
+	ld a, [hl+]
+	ld e, a ; e = x
+	inc hl ; skip height
+
+	ld a, [hl]
+	add a, e ; e = x + width
+	ld e, a 
+	ret
+
 	; tests if a point is inside r1
+	;		 a: mask
 	;		bc: y/x point
 	;		hl: rectangle
 	;	returns:
 	;		a == 1: inside
 	;		a == 0: not inside
 rect_point_test:
-	ret
+	; check collision mask
+	ld d, a
+	ld [hl], a
+	and a, d
+	; exit if mask is no match
+	jp z, @no_collision_mask_match
+	
 
+	ret
+@no_collision_mask_match:
+	xor a, a
+	ret
 	
 	; removes a rectangle
 	; inputs: